Merge pull request #885 from projectxmaker/master

MongoDB - loopback.getCurrentContext() returns null

Close #885
Fix #809

server/middleware/context.js

@@ -2,6 +2,7 @@ var loopback = require('../../lib/loopback');
 var juggler = require('loopback-datasource-juggler');
 var remoting = require('strong-remoting');
 var cls = require('continuation-local-storage');
+var domain = require('domain');
 
 module.exports = context;
 
@@ -44,6 +45,13 @@ function context(options) {
   var scope = options.name || name;
   var enableHttpContext = options.enableHttpContext || false;
   var ns = createContext(scope);
+
+  var currentDomain = process.domain = domain.create();
+  currentDomain.oldBind = currentDomain.bind;
+  currentDomain.bind = function(callback, context) {
+    return currentDomain.oldBind(ns.bind(callback, context), context);
+  };
+
   // Return the middleware
   return function contextHandler(req, res, next) {
     if (req.loopbackContext) {
@@ -53,13 +61,19 @@ function context(options) {
     // Bind req/res event emitters to the given namespace
     ns.bindEmitter(req);
     ns.bindEmitter(res);
+
+    currentDomain.add(req);
+    currentDomain.add(res);
+
     // Create namespace for the request context
-    ns.run(function processRequestInContext(context) {
-      // Run the code in the context of the namespace
-      if (enableHttpContext) {
-        ns.set('http', {req: req, res: res}); // Set up the transport context
-      }
-      next();
+    currentDomain.run(function() {
+      ns.run(function processRequestInContext(context) {
+        // Run the code in the context of the namespace
+        if (enableHttpContext) {
+          ns.set('http', {req: req, res: res}); // Set up the transport context
+        }
+        next();
+      });
     });
   };
 }

test/loopback.test.js

@@ -1,4 +1,7 @@
 var it = require('./util/it');
+var describe = require('./util/describe');
+var Domain = require('domain');
+var EventEmitter = require('events').EventEmitter;
 
 describe('loopback', function() {
   var nameCounter = 0;
@@ -388,4 +391,72 @@ describe('loopback', function() {
       });
     });
   });
+
+  describe.onServer('loopback.getCurrentContext', function() {
+    var runInOtherDomain;
+    var runnerInterval;
+
+    before(function setupRunInOtherDomain() {
+      var emitterInOtherDomain = new EventEmitter();
+      Domain.create().add(emitterInOtherDomain);
+
+      runInOtherDomain = function(fn) {
+        emitterInOtherDomain.once('run', fn);
+      };
+
+      runnerInterval = setInterval(function() {
+        emitterInOtherDomain.emit('run');
+      }, 10);
+    });
+
+    after(function tearDownRunInOtherDomain() {
+      clearInterval(runnerInterval);
+    });
+
+    // See the following two items for more details:
+    // https://github.com/strongloop/loopback/issues/809
+    // https://github.com/strongloop/loopback/pull/337#issuecomment-61680577
+    it('preserves callback domain', function(done) {
+      var app = loopback();
+      app.use(loopback.rest());
+      app.dataSource('db', { connector: 'memory' });
+
+      var TestModel = loopback.createModel({ name: 'TestModel' });
+      app.model(TestModel, { dataSource: 'db', public: true });
+
+      // function for remote method
+      TestModel.test = function(inst, cb) {
+        var tmpCtx = loopback.getCurrentContext();
+        if (tmpCtx) tmpCtx.set('data', 'a value stored in context');
+        if (process.domain) cb = process.domain.bind(cb);  // IMPORTANT
+        runInOtherDomain(cb);
+      };
+
+      // remote method
+      TestModel.remoteMethod('test', {
+        accepts: { arg: 'inst', type: uniqueModelName },
+        returns: { root: true },
+        http: { path: '/test', verb: 'get' }
+      });
+
+      // after remote hook
+      TestModel.afterRemote('**', function(ctxx, inst, next) {
+        var tmpCtx = loopback.getCurrentContext();
+        if (tmpCtx) {
+          ctxx.result.data = tmpCtx.get('data');
+        }else {
+          ctxx.result.data = 'context not available';
+        }
+        next();
+      });
+
+      request(app)
+        .get('/TestModels/test')
+        .end(function(err, res) {
+          if (err) return done(err);
+          expect(res.body.data).to.equal('a value stored in context');
+          done();
+        });
+    });
+  });
 });